From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f171.google.com (mail-ie0-f171.google.com [209.85.223.171]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id AA5C521F194; Mon, 26 Nov 2012 13:11:25 -0800 (PST) Received: by mail-ie0-f171.google.com with SMTP id 17so14604085iea.16 for ; Mon, 26 Nov 2012 13:11:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:date:message-id:subject:from:to:content-type :content-transfer-encoding; bh=6L447q2CbVVtP7KvSffKPGT1TQT4NcRyNiAwGMaeMXo=; b=UBVDZCEHRG2BvFQDtikMlhCRwksEBh2W2/Bqs90KGJRD2x1crJogqZvZEZ5rWqGCsL c5HY59PoiRFjlExQhatH6yyEoC71PxtLy/aFNWXj2nGXTKmemM/Rbqbnzb8BXWNsLHCe u9Ip0odepjwfgKuD/GMxuye62PTVOjgA6fgmyMaMJbmSnH+J6bQ7E5Tr1aSZ0vBaVKfi o+0fX/EkI5Jd9JnbQe6YH3kDIxXg9feGCpNwdxZuoMC6QEqbUo+IsCRCvR/BvjNGSnBr 6gOPxG2LBSpkPoWUQ6X0ZcetNXr5k4s4T9Jm4LvRcRmkCVt2DkW3qnEKiG8/XrQhBnnK sUeg== MIME-Version: 1.0 Received: by 10.50.157.162 with SMTP id wn2mr13428506igb.27.1353964284507; Mon, 26 Nov 2012 13:11:24 -0800 (PST) Received: by 10.64.135.39 with HTTP; Mon, 26 Nov 2012 13:11:24 -0800 (PST) Date: Mon, 26 Nov 2012 22:11:24 +0100 Message-ID: From: Dave Taht To: bloat , codel@lists.bufferbloat.net, bloat-announce@lists.bufferbloat.net, cerowrt-devel@lists.bufferbloat.net Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Subject: [Codel] DOCSIS + Codel paper published by cablelabs X-BeenThere: codel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: CoDel AQM discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Nov 2012 21:11:26 -0000 Recently Greg White and a few others at Cablelabs, along with Kathie Nichols, did an exhaustive simulation of a cable modem with a default amount of buffering, vs the new short queue option, vs codel, in a wide variety of scenarios. The paper has just been released officially. http://www.cablelabs.com/downloads/pubs/PreliminaryStudyOfCoDelAQMinaDOCSIS= Network.pdf If you dig deeply into it, you'll see how really small queues can hurt performance (so don't do that), the effect of losing TCP syns in drop tail (don't saturate your buffers!), the effects of overbuffering at the driver level (hard to tell what reducing that will do in this sim), and a few other things like that. One problem with the web portion of the sim is that it doesn't simulate enough streams, and more importantly, it doesn't emulate the effects of DNS lookups. Still, it's interesting and more accurate than many others tests. I'm relatively happy with the voip test therein, although I structured the rrul equivalent to be much more difficult than the simulated one. And if you look at the (fairly few) places in the paper where codel doesn't shine, and think about where fq_codel compensates for that, you might go to bed with a glow on. I look forward to the followup paper. Thx cablelabs and kathie! --=20 Dave T=E4ht Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.= html